At 16 years old, handsome, with good looks and a good fashion sense, the only thing Ikumi lacks is money. Although from Jupiter, an area associated with wealth and prestige, Ikumi claims to be poor and thus remained on the Liebe Delta for the Dive Break despite his friend Kouji's expectations that Ikumi would go home. Ikumi is an excellent piloting student and out of the entire Level 2 class, ranked second in the piloting exams (Kouji's brother Yuki took first place). Charismatic, Ikumi is the 'leader' of Kouji's circle of friends, and has taken notice of Kozue Izumi, his would-be girlfriend. He is Kouji's roommate, both aboard the Liebe Delta and the Ryvius, and the two are good friends. Ikumi is also the main operator for the Vital Guarder, coordinating the other four.
Ikumi is the fourth and last in a successive line of captains aboard the Ryvius, following in the footsteps of such varied individuals such as Lucson Houjou, Aires Blue and - most recently - Juli Bahana. Despite his easy-going, good-humoured nature, Ikumi harboured a dark secret. During his time living a wealthy lifestyle on Jupiter, he fell in love with his own sister. As the current society forbade incest, Ikumi's sister committed suicide, and Ikumi himself relocated to the Liebe Delta soon after. Such a tramatic event in his past made Ikumi very protective of others, towards the point of insanity. This, combined with the increasing amount of violence aboard Ryvius and the brutal assault of his girlfriend, made him a coldhearted leader who cannot seem to distinguish between his allies and enemies, even going so far as to shoot his own friend.